Hi guys, I have a 2014 Corvette that I picked up as a project that had front end work from an accident but was assembled before I got it. I took it in for an alignment to start to get the car ready for the road again and they were able to put it in spec but said my SAI on the left was at max. Frame has been measured and confirmed good. 90 percent of parts on front end are new and before I go replacing a lower control arm assembly or a hub on the left side I have a question. Can the steering axis inclination be adjusted or affected by the upper control arm? It appears there may be spacers in between the upper control arm mounts and the frame. If an incorrect spacer was used or mistakenly not put in when the front end was being reassembled would this affect SAI readings??

 

There are spacers between the UCA and the frame. They are used along with the cams in the LCA mounts to adjust camber and if you use unequal amounts between the front dog bone and ther rear dog bone can help set caster.

Bill

 

Thanks Bill. Do you know if this would change SAI readings though??

Also because this has been apart I have no idea what a stock configuration looks like or where one gets the proper spacers if they do want to change an adjustment.

Jay

 

Here is the alignment sheet. Any advice is appreciated.

 

Does anyone have experience with alignments for these cars? I would love to get this figured out instead of just throwing money at changing pieces for no reason.

 

Ttt

 

Yes, the upper control arm can affect your SAI.

To answer your question directly, Yes the movement of the upper control arm forwards or backwards will change your SAI.

 

So the dog bones can be moved ahead or backwards?? I did not realize they were oval and thought you could only shim away from the frame or take shims out to bring the control arm closer.

Sorry for the questions but just want to learn as much as I can because there are clearly some alignment shops around here that do not know either.

 

No - the holes in the dog bones are not oval! Below is a picture of my C7 Front Left UCA - I had it apart yesterday while installing a stud kit:





Like Bill Dearborn said: "if you use unequal amounts between the front dog bone and the rear dog bone can help set caster", i.e., if you put more washers/shims between the forward dog bone and the frame you will move the front leg of the UCA outward, which will move the top ball joint to the rear - increasing positive caster.

And of course you can put additional washers/shims between the dog bone and frame on all four of the dog bone attach points to push the UCA out, which will move the top of the ball joint out, which should reduce your SAI. And that will change your camber as well.

BTW - you're concentrating on the front end due to the repairs that were made there, but don't forget the rear wheel alignment. The C7 rear caster is adjustable, and it's important to get it in spec and the same both sides. Most alignment shops won't even know what you're talking about when you tell them to check and set rear caster, but there are several threads on the forum with excellent info about it, so do some research about rear caster so you can make sure your shop (or you, if you're doing your own alignments) are aware of what to measure and how to adjust it.
.

 

BEZ06 thanks for the detailed reply explaining the use of washers and the impact they have on caster and SAI as well as rear caster!